How many air changes per hour (ACH) do we need, and how do we determine how many HEPA-CARE units we need to provide the required ACH?
• CDC requires at least 12 ACH in any renovated or new isolation rooms (PE or AIIR), a minimum of 6 ACH in existing isolation rooms and at least 15 ACH in operating rooms (including 3+cfm of fresh air). Most facilities target at least 12 ACH even in existing rooms. One or more HEPA-CARE systems may be needed, depending on the size of the room in cubic feet (length x width x height to the drop ceiling). As with any air filtration device (AFD), factors such as filter loading, attached collars or ducting and reduced voltage to the motors will decrease actual delivered airflow.
